Field of the Invention
The present invention relates to methods of simultaneously forming grooves in, and flattening and/or texturing, a golf club face, and golf club heads having faces with grooves and surface texturing. In particular, the present invention is directed to a process that simultaneously flattens a golf club face and adds grooves and natural and/or or post-finished micro-features using one cutting tool and a single-part machine setup.
Description of the Related Art
Grooves on golf club head faces, particularly iron-type golf clubs, allow the golfer to control the spin and launch angle of a golf ball upon impact with the face, and also help to channel debris away from the face of the golf club head. The prior art reveals many methods of forming grooves on faces, including the milling techniques taught in U.S. Pat. Nos. 7,273,422 and 8,578,980 and those used to create grooves in the Callaway Billet Series Entirely Milled Wedge sold in the late 1980s. In each of these examples, cutter 30 is used to form grooves 20 in the face 10, such that each groove 20 includes a lead-in radius 22 or edge geometry approved by the USGA, and is separated by a flat face portion 15, as shown in FIGS. 1 and 2. The cutter 30 turns at an axis 14 that is parallel to, or nearly parallel to, the face 10.
Generally, groove milling is preceded by fly-cutting the golf club face, an operation intended to ensure face flatness before grooves 10 are added. In this process, known as “vertical milling,” a cutting tool 35 is oriented at an axis 12 that is perpendicular to the face 10, as shown in FIG. 3. Before the grooves 20 are added, manufacturers often purposely retain the machine marks in the face that may result from the face fly-cutting operation. These marks are meant to add texture to the face to improve spin control, as well as cosmetic appeal. As shown in prior art clubs such as the Callaway Billet Wedge, the fly-cutting tool 35 often leaves a distinctive rotary pattern on the face dependent upon the feeds and speeds, diameter, and the tip of the fly-cutter 35 used to flatten the face. These features are commonly referred to as micro-features or micro-grooves. These features can also be created in a third step, which may be performed before or after the grooves 20 are added, via laser, chemical milling, blasting, ablating, or other techniques known to a person skilled in the art.
The vertical milling operation typically is performed using a different set-up, technique, and/or machine than that used to form the face grooves 20, which can create golf club face 10 inconsistencies and unwanted marks. In fact, with these prior art techniques, maintaining consistency becomes time-consuming and costly, and must be performed by an experienced machinist or advanced technician. Without this experience, and the use of high precision tooling, these prior art techniques also do not provide a reliable way to control the edge deviation of each groove 20, such that higher performance (more steeply angled) grooves 20 are more likely to be nonconforming with USGA standards when they are formed using the prior art techniques described herein. Therefore, there is a need for a method of efficiently adding grooves and surface texturing to a golf club face without introducing inconsistencies or requiring a skilled technician to oversee production.